0:00:02 > 0:00:04My name's Steve Backshall!
0:00:06 > 0:00:09And THIS is Deadly Pole To Pole.
0:00:09 > 0:00:11Oh!
0:00:11 > 0:00:13From the top of the world to the bottom.
0:00:13 > 0:00:15Whoa! Ha-ha!
0:00:15 > 0:00:17Deadly places.
0:00:17 > 0:00:18Deadly adventures.
0:00:18 > 0:00:20And deadly animals.
0:00:21 > 0:00:24And you're coming with me every step of the way!
0:00:26 > 0:00:27Argh!
0:00:30 > 0:00:34Our expedition's made its way to California's Pacific coast.
0:00:34 > 0:00:38The marine dream, primeval predators and a shiver of sharks.
0:00:40 > 0:00:42'California may be known for its beach life,
0:00:42 > 0:00:45'but it's what's further out to sea that I'm interested in.
0:00:47 > 0:00:50'Around 3,600 miles into our journey,
0:00:50 > 0:00:54'we're hitting the San Diego coast on an underwater adventure
0:00:54 > 0:00:56'to find peculiar Pacific predators.'
0:01:01 > 0:01:05'Whilst here, I dive with impressive ocean acrobats.'
0:01:05 > 0:01:07Whoa! That was quick!
0:01:08 > 0:01:11'And hunt out a clumsy looking killer.'
0:01:11 > 0:01:13Incredible. Simply incredible.
0:01:15 > 0:01:17'But we start in super-charged style,
0:01:17 > 0:01:20'with the fastest shark in the seas, the mako.'
0:01:22 > 0:01:25The mako is not only the fastest shark,
0:01:25 > 0:01:28it's also one of the fastest of all fish.
0:01:28 > 0:01:30There are very, very few that can match it.
0:01:30 > 0:01:32As an idea of how fast they can go,
0:01:32 > 0:01:36right now our boat's doing about 35km an hour.
0:01:36 > 0:01:38Well, the mako does 50,
0:01:38 > 0:01:42and could cruise straight past us as if we were standing still.
0:01:42 > 0:01:44That is a seriously fast fish!
0:01:48 > 0:01:49'The seas are flat calm,
0:01:49 > 0:01:53'making it easier for us to spot fins breaking the water.'
0:01:54 > 0:01:57Oh, my goodness!
0:01:57 > 0:02:01We've just come upon a big pod of bottlenose dolphins.
0:02:02 > 0:02:06Oh, wow! They're going absolutely crazy all around us.
0:02:06 > 0:02:08Looks like they could well be feeding.
0:02:08 > 0:02:10And it's too good an opportunity to miss.
0:02:10 > 0:02:13They're not the animal we came here to find but we have to hop
0:02:13 > 0:02:17overboard and see if we can get some shots of them underwater.
0:02:17 > 0:02:21Bottlenose dolphins, just one of the best animals in the world.
0:02:30 > 0:02:32'Jumping in alongside the pod,
0:02:32 > 0:02:36'we're instantly surrounded by delightful dancing dolphin.
0:02:36 > 0:02:39'They are the most enchanting of beasts.
0:02:39 > 0:02:42'Their acrobatic skills help them snap up shoals of fish.
0:02:42 > 0:02:45'But now they're simply fooling around.'
0:02:49 > 0:02:54That is one of the great wildlife encounters.
0:02:54 > 0:02:58Bottlenose dolphins are the circus performers of the Deadly world.
0:02:58 > 0:03:01One second they're a clown, the next minute they're an acrobat.
0:03:01 > 0:03:04But there's no taking away from the fact that these are one
0:03:04 > 0:03:08of the fastest, most intelligent, lethal beasts on earth.
0:03:10 > 0:03:14'Seeing such a large pod of dolphin is a sure sign that these seas are
0:03:14 > 0:03:16'teeming with fish for them to feed on.
0:03:16 > 0:03:19'And that also bodes well for our mako shark mission.'
0:03:22 > 0:03:25We're now about nine miles out in the open sea,
0:03:25 > 0:03:28we've cut the engines and we're just drifting with the tide.
0:03:28 > 0:03:32And what we're going to do is get this stuff into the water.
0:03:32 > 0:03:36This is essentially the old chunks of fish that nobody wants,
0:03:36 > 0:03:39and it's going to create a slick of lovely fishy goo that goes
0:03:39 > 0:03:43out behind the boat, and hopefully, attracts in our sharks.
0:03:43 > 0:03:46Once it's in the water, all we have to do is watch and wait.
0:04:01 > 0:04:04I think we might have something.
0:04:04 > 0:04:07There was just a fin came up alongside the bait.
0:04:10 > 0:04:13I don't know. Certainly didn't see it clearly enough
0:04:13 > 0:04:17to say even that it was a shark, let alone it was a mako.
0:04:17 > 0:04:20'If it is a mako, we're going to have to kit up quickly.
0:04:22 > 0:04:24'These sharks do not hang around.'
0:04:26 > 0:04:29I'm going to be putting on some dark gloves
0:04:29 > 0:04:30to cover up the white of my fingers.
0:04:30 > 0:04:34The last thing you want when you're in the water with these animals
0:04:34 > 0:04:37is fingers which look kind of like white sardines,
0:04:37 > 0:04:39and therefore food, in its face.
0:04:50 > 0:04:54'But the first shark shape did not stay long.
0:04:54 > 0:04:56'All we see is the deep blue sea.'
0:04:56 > 0:05:00At the moment, our mako shark seems to have disappeared.
0:05:00 > 0:05:03Haven't seen him for quite a while now.
0:05:04 > 0:05:07'Wildlife watching is all about patience.
0:05:07 > 0:05:09'We decide to give it a while longer.'
0:05:16 > 0:05:19'Then another distinctive silhouette appeared.'
0:05:23 > 0:05:27'It's a blue shark. It may have swum in from many miles away.'
0:05:33 > 0:05:37'It's a long, thin species built for cruising the open ocean,
0:05:37 > 0:05:39'catching the few fish they find.'
0:05:42 > 0:05:44This is absolutely wonderful.
0:05:45 > 0:05:48There's at least two blue sharks around us now.
0:05:50 > 0:05:52They are so aptly named.
0:05:52 > 0:05:57They have the most glorious blue shade to the skin. It almost...
0:06:01 > 0:06:05That one just nudging my camera now, look at that!
0:06:05 > 0:06:07He's right in my face!
0:06:07 > 0:06:09They're sort of like...
0:06:09 > 0:06:13the equivalent of a puppy dog.
0:06:13 > 0:06:15So inquisitive, so interested!
0:06:15 > 0:06:18Just sticking their noses in absolutely everything.
0:06:20 > 0:06:22They're fabulous animals.
0:06:24 > 0:06:27'These sharks have such a curious nature.
0:06:27 > 0:06:30'And that's part of their deadly strategy.
0:06:30 > 0:06:33'Drawn in by the electrical pulses coming from the cameras,
0:06:33 > 0:06:35'they're keen to check us out,
0:06:35 > 0:06:38'see if we might offer a small bit of food in this vast ocean.'
0:06:43 > 0:06:45'Suddenly, the two tiddlers give way to a blue
0:06:45 > 0:06:47'that's the biggest I've ever seen.
0:06:49 > 0:06:52'He's over three metres long and seems to have no fear.
0:06:53 > 0:06:56'But far from trying to sneak a bite out of me, he seems
0:06:56 > 0:06:59'inquisitive, intrigued, even friendly.'
0:07:01 > 0:07:02I keep ducking down with my mask
0:07:02 > 0:07:05because he was coming ever so close to us.
0:07:05 > 0:07:08But he's so gentle, so placid!
0:07:08 > 0:07:12And these creatures really have individual personalities.
0:07:12 > 0:07:17It's not surprising. Any predator has to have a good sized brain.
0:07:17 > 0:07:20They have to have processing power to figure out problems,
0:07:20 > 0:07:22to figure out how to catch their prey.
0:07:22 > 0:07:23You can see that that big brain
0:07:23 > 0:07:26has developed a big personality in this shark.
0:07:26 > 0:07:31It really is just like - I don't know - a friendly dog.
0:07:31 > 0:07:33I think I might have a new favourite animal.
0:07:36 > 0:07:37'Blue sharks have won our hearts,
0:07:37 > 0:07:41'but they certainly haven't demonstrated their deadly abilities.
0:07:43 > 0:07:46'After hours in the water with the blues,
0:07:46 > 0:07:49'we begin to give up hope of seeing a mako.
0:07:53 > 0:07:57'Until the crew on deck spot another shape fast approaching.'
0:07:57 > 0:07:59Mako shark!
0:07:59 > 0:08:01Coming right at 'em, coming right at 'em!
0:08:04 > 0:08:07'The mood in the water instantly changes.
0:08:08 > 0:08:11'These sharks have a wholly different demeanour.
0:08:11 > 0:08:12'They're feisty and foreboding.'
0:08:15 > 0:08:17Look at the attitude of the mako shark.
0:08:17 > 0:08:20It's so different to that of the blue.
0:08:20 > 0:08:23'These sharks are not interested in playing.
0:08:23 > 0:08:25'They smell blood and are primed,
0:08:25 > 0:08:27'ready to explode into action at any time.'
0:08:29 > 0:08:32And they're such a sinister shark.
0:08:32 > 0:08:35The two of them are patrolling around us.
0:08:35 > 0:08:38One second they're there, the next second they're gone.
0:08:38 > 0:08:40They just disappear into the blue.
0:08:41 > 0:08:44'The speed of these makos is insane.
0:08:44 > 0:08:46'A couple of thrusts of their crescent-shaped tail,
0:08:46 > 0:08:48'and they explode forwards.'
0:09:04 > 0:09:06I don't think I've ever seen anything like it.
0:09:06 > 0:09:09Even sailfish and tuna don't look as fast as mako underwater,
0:09:09 > 0:09:13like a falcon or a cheetah or a racehorse.
0:09:13 > 0:09:15It just always looks like it's on edge,
0:09:15 > 0:09:18always looks like it's ready to burst out into speed.
0:09:22 > 0:09:26'Their speed means they can outsprint a huge range of prey,
0:09:26 > 0:09:31'including dolphins, other sharks and turtles. And they're sneaky,
0:09:31 > 0:09:34'attacking their prey from below with a vertical lunge,
0:09:34 > 0:09:36'biting down hard,
0:09:36 > 0:09:39'leaving the animal to bleed to death before coming in to feed.'
0:09:41 > 0:09:44This is without doubt one of the most impressive predators
0:09:44 > 0:09:47you'll ever see anywhere in any environment.
0:09:49 > 0:09:51'So different from the blues.
0:09:51 > 0:09:54'These sharks come in with an angular, agitated movement.
0:09:54 > 0:09:57'There's no doubt they mean business.
0:09:57 > 0:10:01'And they've got a face full of sharp teeth that almost seem to be
0:10:01 > 0:10:02'spilling out of their mouths,
0:10:02 > 0:10:05'adding to their chilling impression.'
0:10:06 > 0:10:07The mako shark.
0:10:07 > 0:10:12A shark that can go from cruising to exploding
0:10:12 > 0:10:16in the blink of an eye, is without doubt deadly.
0:10:16 > 0:10:18'The fastest sharks in the sea.
0:10:20 > 0:10:22'Jaws overflowing with gnarly teeth.
0:10:25 > 0:10:26'And a sneaky, speedy attack.
0:10:29 > 0:10:32'Makos are speedy killers of the California coast.'
0:10:36 > 0:10:40'Our next aquatic adventure takes place much closer to the shore,
0:10:40 > 0:10:44'with a synchronised swimmer that's blessed with super senses.'
0:10:45 > 0:10:49The classic carnivore of the California coast is an animal
0:10:49 > 0:10:51that really doesn't have any problem with people.
0:10:51 > 0:10:52In fact, here in San Diego,
0:10:52 > 0:10:55they can be found living a stone's throw from the city.
0:10:55 > 0:10:59It's that most playful of predators, the California sea lion.
0:11:02 > 0:11:06'Mature males could weigh five times my body weight.
0:11:07 > 0:11:12'On land, they're a regular seal out of water, lumbering, clumsy.
0:11:12 > 0:11:14'But that's just a tiny part of the seal story.'
0:11:16 > 0:11:19This rocky outcrop is what's known as a haul-out.
0:11:19 > 0:11:21It's a place the sea lions come to recover their energy after
0:11:21 > 0:11:26fishing trips. The water around me is full of sea lions.
0:11:26 > 0:11:27When they're under the water,
0:11:27 > 0:11:29they're a completely different animal,
0:11:29 > 0:11:32transformed by their ability to hunt in the water.
0:11:32 > 0:11:33So that's where we have to go next.
0:11:38 > 0:11:40Usually on Deadly, we go out of our way
0:11:40 > 0:11:43to go to the most wild, remote places on the planet.
0:11:43 > 0:11:46Today we're doing things a little bit differently.
0:11:46 > 0:11:49We're diving right on the edge of the city of San Diego.
0:11:52 > 0:11:54The main haul-out of the sea lions is just around this corner.
0:11:54 > 0:11:56So we're going to have to time the waves just right,
0:11:56 > 0:11:58wade in here, dive round,
0:11:58 > 0:12:01and hopefully we'll get an extraordinary underwater encounter.
0:12:02 > 0:12:04'It's pretty odd, in my full dive kit,
0:12:04 > 0:12:07'wandering past sunbathers and sandcastles,
0:12:07 > 0:12:11'but the best sea lion encounter is only just off the beach.'
0:12:14 > 0:12:15Ohh!
0:12:23 > 0:12:27All the animals around me at the moment are females.
0:12:27 > 0:12:30They're extremely elegant. Ballet dancers of the deep.
0:12:30 > 0:12:33But all the tricks they're using
0:12:33 > 0:12:36to twist and turn through the water are exactly
0:12:36 > 0:12:39the same ones they use when they're chasing their prey.
0:12:43 > 0:12:45Whoa! That was quick!
0:12:48 > 0:12:52Every once in a while, a sea lion will zip in at speed
0:12:52 > 0:12:57and stick its nose right in your camera or in your face.
0:12:57 > 0:13:01It's almost like they're showing off.
0:13:01 > 0:13:05They're showing you how much faster and more agile they are than you.
0:13:05 > 0:13:10'These tussles and play fights can be about dominance, mating,
0:13:10 > 0:13:12'or training for catching food.'
0:13:12 > 0:13:15So much play fighting goes on between these animals.
0:13:15 > 0:13:18They've got ferocious teeth.
0:13:18 > 0:13:22But these animals have a thick layer of blubber and hair,
0:13:22 > 0:13:27which keeps them insulated and also keeps them safe from friendly nips.
0:13:27 > 0:13:30And if I was to get bitten by one it would hurt like heck!
0:13:31 > 0:13:34'That bite is just one element of their deadly side.'
0:13:36 > 0:13:38Sea lions are perhaps the most underrated
0:13:38 > 0:13:42and underestimated of large carnivores on the planet.
0:13:42 > 0:13:45The reason they're called sea lions is that they have teeth
0:13:45 > 0:13:49which wouldn't look out of place in the mouth of a big cat.
0:13:49 > 0:13:52They're one of the finest fishermen on the planet.
0:13:56 > 0:14:00'Sea lions catch individual fish in relatively short chases,
0:14:00 > 0:14:06'but can hunt continuously for 30 hours, showing remarkable endurance.
0:14:06 > 0:14:09'They'll dive down to 200 metres in search of fish and squid.'
0:14:10 > 0:14:13'They detect movement in the water using their whiskers,
0:14:13 > 0:14:16'many times more sensitive than those of a cat.
0:14:16 > 0:14:19'The vibrations lead them straight towards their prey.'
0:14:20 > 0:14:23Oh!
0:14:23 > 0:14:25That's a male California sea lion.
0:14:25 > 0:14:28He is absolutely enormous!
0:14:30 > 0:14:34A male sea lion of that size could weigh five or six times
0:14:34 > 0:14:37my body weight, and is enormously powerful.
0:14:40 > 0:14:44'Their physical prowess is matched by their intelligence.'
0:14:46 > 0:14:48Sea lions are mammals,
0:14:48 > 0:14:53and like any good-sized mammal predator,
0:14:53 > 0:14:56they need to have a big brain to deal with
0:14:56 > 0:14:58the problems of finding their food.
0:14:59 > 0:15:04And because of that big brain, they're also very social animals.
0:15:07 > 0:15:10'Sea lions have everything going for them.
0:15:10 > 0:15:12'They simply outgun everything in their world.
0:15:14 > 0:15:16'With their giant size...
0:15:18 > 0:15:22'..teeth that wouldn't look out of place in the mouth of a real lion,
0:15:22 > 0:15:24'and acrobatic abilities...
0:15:26 > 0:15:29'..these sea lions are sleek, clever,
0:15:29 > 0:15:31'streamlined and...'
0:15:31 > 0:15:32'Deadly.'
0:15:34 > 0:15:38'This stretch of coastline is one of the best places on the planet
0:15:38 > 0:15:42'to immerse yourself in an other-worldly dreamscape.'
0:15:42 > 0:15:45We're bound for one of the most exciting of all environments.
0:15:45 > 0:15:47It's kind of the equivalent of a cloud forest
0:15:47 > 0:15:51with stunning light, and haunted by strange predators.
0:15:51 > 0:15:53The only real difference is, it's underwater.
0:16:00 > 0:16:02'We're heading out to track down a venomous,
0:16:02 > 0:16:06'glamorous alien in a beautiful submarine jungle.
0:16:08 > 0:16:10'There's not much hint from the surface of how special
0:16:10 > 0:16:12'what lies beneath really is.'
0:16:38 > 0:16:41It's like being in some weird orange cave.
0:16:45 > 0:16:50This extraordinary, dense forest is kelp.
0:16:50 > 0:16:54It looks like a plant, but it's actually much more closely
0:16:54 > 0:16:56related to the algaes
0:16:56 > 0:16:58and it's probably the fastest-growing living thing
0:16:58 > 0:17:00on the planet.
0:17:00 > 0:17:05In ideal conditions, it could grow as long as my arm in a single day.
0:17:06 > 0:17:11This forest is home to an enormous amount of exciting animals.
0:17:15 > 0:17:18This is a giant black bass.
0:17:18 > 0:17:20It's a huge fish.
0:17:20 > 0:17:24It looks like it could swallow my head in one single mouthful.
0:17:25 > 0:17:29They are predatory but do most of their hunting by night.
0:17:29 > 0:17:34And I don't think he's interested in us. Well, not to eat, anyway!
0:17:34 > 0:17:35He's certainly curious.
0:17:37 > 0:17:38Fabulous creature.
0:17:39 > 0:17:42'But my target animal could not be more different.'
0:17:51 > 0:17:55In many ways, a kelp forest is similar
0:17:55 > 0:17:58to a conventional forest.
0:17:58 > 0:18:00Down on the sea bed you have holdfasts
0:18:00 > 0:18:03that work almost like roots to anchor the kelp in place.
0:18:03 > 0:18:09Up here, it's like the canopy, blessed by sunlight,
0:18:09 > 0:18:13which gives it all the energy it needs to grow.
0:18:17 > 0:18:19We descend to the base of the kelp -
0:18:19 > 0:18:22it's the equivalent of the forest floor.
0:18:22 > 0:18:24Little light penetrates down this far.
0:18:24 > 0:18:26We need to stick close together here, guys.
0:18:26 > 0:18:28It'd be really easy to get lost.
0:18:35 > 0:18:38The woods down here are full of plankton.
0:18:38 > 0:18:43You can see all of these tiny morsels in the water are actually
0:18:43 > 0:18:48living creatures but they are greatly decreasing the visibility
0:18:48 > 0:18:51so you really can't see very much.
0:18:55 > 0:18:58It makes it all rather spooky and sinister.
0:19:00 > 0:19:04This creepy underworld is home to many mysteries,
0:19:04 > 0:19:07but not yet the one we're seeking.
0:19:07 > 0:19:08But at the edge of the forest,
0:19:08 > 0:19:12where kelp meets open ocean, we find our marine murderer.
0:19:18 > 0:19:21This is an unusual and beautiful predator
0:19:21 > 0:19:24to find lurking in amongst the kelp.
0:19:27 > 0:19:30It's a black sea nettle jellyfish.
0:19:30 > 0:19:34And it's pretty big.
0:19:34 > 0:19:37It stretches out over five metres
0:19:37 > 0:19:40from the end of the skirt to the head of the bell here.
0:19:43 > 0:19:47And it is extraordinarily beautiful.
0:19:48 > 0:19:55This area is like the flouncing skirts of a flamenco dancer,
0:19:55 > 0:19:59pink and scarlet.
0:19:59 > 0:20:04Glorious colours, which hide its deadly secret.
0:20:06 > 0:20:09'This gorgeous jellyfish might look glamorous,
0:20:09 > 0:20:12'but it has a hidden lethal side.'
0:20:13 > 0:20:17This part of the jellyfish is known as the bell.
0:20:17 > 0:20:19The top of it is completely harmless
0:20:19 > 0:20:23and it can pulsate that to swim along.
0:20:25 > 0:20:30But these tentacles here are covered with stinging cells
0:20:30 > 0:20:32called nematocysts.
0:20:32 > 0:20:34They're like tiny harpoons linked to a venom sac.
0:20:35 > 0:20:38When they make contact with prey such as fish,
0:20:38 > 0:20:41they'll fire off, ejecting their venom
0:20:41 > 0:20:43and paralysing the prey.
0:20:45 > 0:20:48That then gets delivered to the mouth in here -
0:20:48 > 0:20:50where it's digested.
0:20:50 > 0:20:54'The most venomous of all creatures is a jellyfish.
0:20:54 > 0:20:56'They feed on plankton, fish and other jellies
0:20:56 > 0:21:00'and are also the most ancient, complex animal on earth.'
0:21:00 > 0:21:04They are animals that have been around for a very long time -
0:21:04 > 0:21:06at least 500 million years.
0:21:08 > 0:21:11Way back to the time when the only life on Earth was in the seas.
0:21:15 > 0:21:19The soft, fluid, flowing body shape is surprisingly effective.
0:21:21 > 0:21:25You can see this wonderful, pulsing movement in the bell.
0:21:27 > 0:21:31It can swim using that. Some can swim powerfully enough
0:21:31 > 0:21:36to swim against tides and currents.
0:21:38 > 0:21:42It's certainly not just a blob of jelly.
0:21:44 > 0:21:47Gaudy, glorious, glamorous and prehistoric.
0:21:50 > 0:21:53Paralysing prey with toxic venom,
0:21:53 > 0:21:57delivered with harpoon-like stings
0:21:57 > 0:22:01and an enchanting appearance.
0:22:02 > 0:22:05Black nettle jellyfish are exquisite killers.
0:22:06 > 0:22:07'Deadly...'
0:22:10 > 0:22:13But on closer inspection, this particular predator
0:22:13 > 0:22:17has itself been the victim of another marine muncher.
0:22:17 > 0:22:22This animal here has been preyed on by another predator.
0:22:23 > 0:22:28There have been big chunks taken out of the bell.
0:22:28 > 0:22:31Big mouthfuls. And round here,
0:22:31 > 0:22:35that's almost certainly from another, even stranger predator.
0:22:37 > 0:22:39That's what I'd really like to see.
0:22:50 > 0:22:53Our best chances of finding one are from the surface so it's back
0:22:53 > 0:22:57to the boat and off to scout out this stranger predator.
0:22:57 > 0:22:59One of the most peculiar-looking fish in the ocean.
0:23:03 > 0:23:07It's moving away, quite fast.
0:23:07 > 0:23:08It should be right over here.
0:23:08 > 0:23:13Just spotted from the top deck - a monster sunfish or Mola mola.
0:23:13 > 0:23:17It's a fabulous animal and one which is deadly
0:23:17 > 0:23:21as they feed on some of the most venomous animals on Earth -
0:23:21 > 0:23:22jellyfish.
0:23:22 > 0:23:26Only problem is they don't tend to stay on the surface long
0:23:26 > 0:23:29when divers get in so we have to be careful about how we approach it.
0:23:29 > 0:23:32It's just over there and it's huge!
0:23:32 > 0:23:35About 30 metres that way.
0:23:35 > 0:23:36Can you see him?
0:23:38 > 0:23:42Erm, are you OK for me to drop in, Danny, are we in neutral?
0:23:42 > 0:23:46- We're going to get the head. - It's swimming in our direction.
0:23:47 > 0:23:51All you see is this extended fin, sticking up out of the water.
0:23:51 > 0:23:54I mean it looks like it could be a shark but it isn't.
0:23:54 > 0:23:57It's this wonderful, wonderful bizarre animal
0:23:57 > 0:23:59and once you've seen a sunfish,
0:23:59 > 0:24:02it really is one of the most unusual creatures on the planet.
0:24:02 > 0:24:03Right here.
0:24:03 > 0:24:06We good, Luke? Am I all right to go in?
0:24:06 > 0:24:10Yeah, don't worry about the weight belts - I'd just get in there, boys.
0:24:10 > 0:24:12Right ahead of the boat.
0:24:31 > 0:24:34These sunfish are such bizarre-looking creatures.
0:24:34 > 0:24:36They almost look as if they've been run over by
0:24:36 > 0:24:40a steam roller and are totally flat, with dorsal fins that they
0:24:40 > 0:24:42waggle to move through the water.
0:24:42 > 0:24:45This is the largest of all bony fish.
0:24:45 > 0:24:49They can measure over four metres fin tip to fin tip
0:24:49 > 0:24:51and weigh more than two tonnes,
0:24:51 > 0:24:54but they start off as an egg smaller than a pea.
0:24:54 > 0:24:56In fact they grow more in
0:24:56 > 0:24:59their lifetime than any other animal on Earth.
0:25:03 > 0:25:07Their boggle-eyed, clumsy appearance hides a deadly secret -
0:25:07 > 0:25:08they feed on some of the most
0:25:08 > 0:25:12venomous creatures on the planet...jellyfish.
0:25:16 > 0:25:19They spend a lot of their time in the cold depths of the ocean
0:25:19 > 0:25:21so often come to the surface to warm up.
0:25:23 > 0:25:26Whilst up here they allow fish to come close
0:25:26 > 0:25:28and pick parasites off their skin.
0:25:28 > 0:25:29Sometimes even seabirds.
0:25:37 > 0:25:40I'm going to see if this sunfish will let me to do it as well.
0:25:40 > 0:25:42But for a fish that looks completely uncoordinated,
0:25:42 > 0:25:47it's actually quite fast and really hard to keep up with.
0:25:57 > 0:26:00But then it stops swimming, rolls onto its side,
0:26:00 > 0:26:05and allows me to do the job of cleaning its sandpaper-like flanks.
0:26:12 > 0:26:15The sunfish really seems to enjoy the contact and it will now be that
0:26:15 > 0:26:19little bit more comfortable as it patrols the ocean for its next meal.
0:26:22 > 0:26:26Incredible. Simply incredible!
0:26:26 > 0:26:29He didn't make it easy for us.
0:26:29 > 0:26:34I mean, they swim deceptively fast and keeping up with him
0:26:34 > 0:26:38was taking all the puff I had, but then, finally, when I got up close,
0:26:38 > 0:26:40it just flipped over, lay flat,
0:26:40 > 0:26:44and invited me to pick parasites off its skin.
0:26:44 > 0:26:48It's the same thing fish would do to clean the sunfish.
0:26:48 > 0:26:51When you have a wild animal that actually
0:26:51 > 0:26:53looks for an interaction with you like that,
0:26:53 > 0:26:56it's one of the most special things in the whole world.
0:26:56 > 0:27:02But curious, bizarre, unusual as the Mola mola is as a fish,
0:27:02 > 0:27:05this is an animal that feeds on some of the most venomous
0:27:05 > 0:27:07creatures on Earth - on jellyfish.
0:27:07 > 0:27:12For that reason alone, this wonder of the deep has to be deadly.
0:27:17 > 0:27:21Roaming the depths of the Pacific Ocean.
0:27:21 > 0:27:23Chomping down on a diet of venomous jellyfish.
0:27:25 > 0:27:28And growing more in their lifetime than any other animal on Earth.
0:27:29 > 0:27:34Sunfish are clumsy killers of San Diego's seas.
0:27:34 > 0:27:35'Deadly...'
0:27:37 > 0:27:41'Join me next time as I continue my journey on Deadly Pole To Pole.'
0:27:41 > 0:27:42These fabulous animals!
0:27:58 > 0:28:01Subtitles by Red Bee Media Ltd